From 7de967774bdcf92a683baa41ac27a36a4ccadc2f Mon Sep 17 00:00:00 2001
From: Jaewook Lee <jaewooklee042@gmail.com>
Date: Tue, 23 Apr 2024 18:51:18 +0200
Subject: [PATCH] fname then mesh for io

---
 gustaf/io/meshio.py | 9 +++++----
 gustaf/io/mfem.py   | 4 ++--
 gustaf/io/mixd.py   | 2 +-
 gustaf/io/nutils.py | 4 ++--
 4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/gustaf/io/meshio.py b/gustaf/io/meshio.py
index ad66e6ebc..c2706ae48 100644
--- a/gustaf/io/meshio.py
+++ b/gustaf/io/meshio.py
@@ -84,7 +84,7 @@ def load(fname):
     return meshes[0] if len(meshes) == 1 else meshes
 
 
-def export(mesh, fname, submeshes=None, **kwargs):
+def export(fname, mesh, submeshes=None, **kwargs):
     """Export mesh elements and vertex data into meshio and use its write
     function. The definition of submeshes with identical vertex coordinates
     is possible. In that case vertex numbering and data from the main mesh
@@ -132,10 +132,10 @@ def export(mesh, fname, submeshes=None, **kwargs):
 
     Parameters
     ------------
-    mesh: Edges, Faces or Volumes
-      Input mesh
     fname: Union[str, pathlib.Path]
       File to save the mesh in.
+    mesh: Edges, Faces or Volumes
+      Input mesh
     submeshes: Iterable
       Submeshes where the vertices are identical to the main mesh. The element
       type can be identical to mesh.elements or lower-dimensional (e.g.
@@ -164,7 +164,8 @@ def export(mesh, fname, submeshes=None, **kwargs):
 
     cells = []
     # Merge main mesh and submeshes in one list
-    meshes = [mesh]
+    meshes = mesh if isinstance(mesh, list) else [mesh]
+
     if submeshes is not None:
         meshes.extend(submeshes)
 
diff --git a/gustaf/io/mfem.py b/gustaf/io/mfem.py
index 1b38ac711..c4ca9e890 100644
--- a/gustaf/io/mfem.py
+++ b/gustaf/io/mfem.py
@@ -107,15 +107,15 @@ def extract_values(fname, start_index, n_lines, total_lines, dtype):
         return mesh
 
 
-def export(mesh, fname):
+def export(fname, mesh):
     """Export mesh in MFEM format. Supports 2D triangle and quadrilateral
     meshes. Does not support different element attributes or difference in
     vertex dimension and mesh dimension.
 
     Parameters
     ------------
-    mesh: Faces
     fname: str
+    mesh: Faces
 
     Returns
     ------------
diff --git a/gustaf/io/mixd.py b/gustaf/io/mixd.py
index 60025d8dc..e873e54ce 100644
--- a/gustaf/io/mixd.py
+++ b/gustaf/io/mixd.py
@@ -116,8 +116,8 @@ def load(
 
 
 def export(
-    mesh,
     fname,
+    mesh,
     space_time=False,
     dual=False,
 ):
diff --git a/gustaf/io/nutils.py b/gustaf/io/nutils.py
index b5915c462..f12d359e2 100644
--- a/gustaf/io/nutils.py
+++ b/gustaf/io/nutils.py
@@ -61,14 +61,14 @@ def load(fname):
     return mesh
 
 
-def export(mesh, fname):
+def export(fname, mesh):
     """Export in Nutils format. Files are saved as np.savez().
     Supports triangle,and tetrahedron Meshes.
 
     Parameters
     -----------
-    mesh: Faces or Volumes
     fname: str
+    mesh: Faces or Volumes
 
     Returns
     --------